Desk lamp



FIG. 1 is a perspective view of the desk lamp embodying the new design;

FIG. 2 is a right side view, the left side being a mirror image thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The portions shown in broken lines form no part of the claimed design.

The ornamental design for a desk lamp, as shown and described.